Ohm-Audio BV is officially a full range McIntosh Labs dealer as of 01-01-2021
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McIntosh Labs USA is one of the oldest manufacturers of High End Audio equipment from the USA. Founded in 1949, and still leading in many areas. In one area McIntosh Labs USA is unique, and that is the use of the Autoformer output in amplifiers. Most High End Audio enthusiasts are well aware that most tube amplifiers are equipped with an output transformer. This output transformer is used to convert the high voltage (2,000-10,000 Volt) music signal into a signal of, say, 20 Volts. The voltage drops, and as a result the current increases. Exactly what you need to properly drive a speaker. Transistor amplifiers don't need this, as they already work with a voltage of about 20 volts. Now a speaker is a tricky thing. The speaker does not have a fixed ohmic resistance. If the speaker is marked 8 Ohms on the back, then that is an average. If you were to measure the speaker across all frequencies from 20Hz to 20,000Hz, you would measure values between approximately 6 Ohms and 60 Ohms. The exact value depends on the frequency the speaker needs to reproduce at any given moment. The transistor amplifier can cope with that, but the transistor amplifier doesn't like it. It prefers a straight, ohmic load, such as 4 Ohms. Or 8 Ohms.
The Autoformer
Most McIntosh Labs transistor amplifiers are equipped with an output transformer, the Autoformer. This specially wound transformer provides a perfect ohmic load for the transistors, so the amplifier always sees the ideal output impedance and is thus optimally configured. The amplifier always sees exactly 8 Ohms. On the other side of this Autoformer are various outputs that form the connection with the connected speakers.
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2021-12 Ohm Audio BV
